To appreciate fully the importance of and the need for this Bill it should be noted that most of our legislative provisions dealing with criminal insanity date back to the 19th century and some to the early 1800s. However, the origins of the insanity defence actually go back much further, they can be traced back at least to the 13th century. However, even with that early realisation of the difficulty, the common law was very slow to recognise a defence to a criminal charge based on insanity. Whatever amelioration it did provide from the severity of the sentence, the quality of mercy tended to be somewhat strained until at least the 18th century.